Electrically operated lathe



R. D. SHAW .June 18, 1932 :ELECTRICALLY OPERATED LATI-IE Filed Dec.

l, 1935 2 Sheets-Sheet l `lum-2 18, 1935. R. D. SHAW 2,005,509

ELECTRICALLY OPERATED LATHE Filed Dec.. 1, 193s 2 sheets-sheet 2 /57 Mae /5'7 INVENTOR R. D. SHA w ELECTRCALLY UPERA'llElD ILATFHE Robert D. Shaw, Hartford, Conn., assignor to Pratt & Whitney Company, Hartford, Conn., a

corporation of New .llersey Application December l, 1933, Serial No. 700,519

12 Claims.

`'Ihis invention relates to machine tools and particularly to an automatic metal turning lathe controlled by electrically operated means so that the movable slide members, as well as the starting and stopping of rotation of the spindle, may be operated in accordance with a predetermined cycle.

More particularly this invention relates to improvements in the automatic lathe shown and describedin my copending application Serial No. 665,566 filed April 1l. 1933 of which this application constitutes a continuation in part.

One object of the present invention is to enable the rear tool slide of an automatic lathe,

^ such as described in the above referred to application, to be started on its cutting stroke at any point of or during any portion of the cutting movement of the main slide or front carriage, and then to return to its initial position on completion of the 'cutting stroke, in the regular cycle or at any prearrangedtimein the cycle.

AInthe previous machine the work supporting spindle is arranged to be rotated through gearing connections with the clutch magnets, but is here rotated by an independent clutch magnet. Therefore, a further object of* importance in the present improvement is the arrangement whereby the work supporting and rotating vtill spindle is idle except during the cycle of movements and is arranged to be started and stopped (by energizing and deenergizing the clutch magnet) by switches in suitable controlling circuits brought into action at the start of or during the cycle. Preferably when the cycle of operations is initiated the spindle rotation is started and may be stopped when the cycle is completed or more particularly when the cutting portion thereof is completed, after effecting the successive cutting operations. A further novel feature is that when the clutch magnet for rotating the spindle is deenergized, rotation of the spindle is stopped instantly by means of an interlocked electrically controlled magnetic brake. Incidentally', by this arrangement the brake is utilized to hold theyspindle while the nished piece is being removed and a new work piece is being inserted. l

In the machine of the previous application the rear slide is brought into the cycle by starting its in movement atthe end of the forward movement of the front carriage which under some circumstances involves an unnecessary delay. Therefore, in order to shorten the cycle, a

provide an adjustable abutment mounted on the longitudinally movable front carriage, and arranged to operatively .engage a switch or contact carrying lever in the controlling circuit for the rear slide so that the in movement of the latter may be started at any selected point in the travel of the front carriage. The movement for the return of the rear slide to initial position after the cutting opei'ation may, however, take place as previously described, or at any suitable time in regular sequence in the cycle. It is preferable that the in movement of the front and rear tool slide and the forward movement ofthe front carriage shall operate at normal speeds, but when the movements are to be reversed in the cycle and the carriage and slides are to be returned to their initial or starting positions, the rapid traverse clutch magnets are brought into action, as described in the previous application, after the respective cutting strokes are completed. The return movements are stopped upon the opening of the high potential contact switches at the end of the respective movements, or when the slides and carriage reach their prearranged starting positions, as in the above referred to application.

The present improvement also employs substantially similarly arranged magnetic clutches for operating the various slides, carriages' or movable elements of the lathe, as described -in the above referred to application, but in addition, a magnetic clutch is provided for `rotating the work spindle, this clutch magnet being preferably operated by aseparater motor suitably mounted on the machine, but obviously the spindle clutch may be geared with the other clutch magnets if desired. Between the spindle motor and the clutch magnet, the usual or any suitable change gears may be installed so that A the spindle may be rotated at any desired spee when its clutch magnet is energized. In the present instance an' important advantage is obtained by operating the. work spindle fromA a separate clutch magnet so that its speed may be changed more-readily, and in particular its rotation may be started and stopped with the cycle of movements of slides. Furthermore, the present arrangement provides an added feature, that is stopping the spindle quickly and maintaining or holding it against rotation during the loading of the machine. 'Ihis is facilitated, as previously indicated, by providing a suitable magnetic brake, 'and preferably the circuits for the clutch magnet for rotating the spindle and the magnet for operating the brake are interlocked so that when one is energized, the other is deenergized.

As in the automatic lathe described in the above referred to application, it is preferable to arrange the movements of the carriage and its tool slidelso that the in movement of the slide takes place and the tool is moved into position for the cutting operation (depth of cut) on the work, and immediately this is followed by the forward movement (to the left in form shown) ofthe front carriage whichmovement continues through the cutting operation or until a predetermined point in the forward movement of the carriage is reached, at which point the out movement of the cross slide is started. In this statement motions of the rear cross slide have been ignored for these may be eliminated as hereinafter explained.

Similarly, as in the previous machine, the movements of the Acarriage or main slide and the respective cross slides are governed by rotating magnetic clutches, the magnets of which are arranged to be energized successively or at prearranged intervals to effect the required movements in the cycle. Preferably energization of the clutch magnets, and hence all movements of the carriage or slides are governed by controlling means carried upon and operated by movements of the slides themselves. The clutches may be operated in succession or otherwise by the automatically operated switches in circuits which preferably are arranged to operate relays controlling the energizing of the respective magnetic clutches.

It will be understood that, as in the previous machine, one type of switch is used for controlling the forward and in movements, controlled through relays, and another group for controlling the magnetic, clutchesA for eiecting the return movements of the slide's and carriage under rapid traverse. It is found preferable when the slides and carriage are thus returned to their initial or starting positions, to stop the respective movements when the slides and carriage reach predetermined positions by means of limit switches in the clutch circuits substantially similar to those on the previous machine, and arranged to be opened individually by movement of the slides and carriage themselves. This arrangement, as previously pointed out, is such that the circuits for each of the rapid traverse clutch magnets are opened without the intervention of relays.

In the application describing the previous machine it was pointed out that after a cycle is completed and the work piece finished, the slides and carriage are all at rest and at their initial positions; the same is true in the present machine, with the additional features that rotation of the spindle is stopped.. Accordingly, in the present machine the finished work, after being turned to the predetermined dimensions, may be removed and a new piece substituted while the spindle is rigidly held against rotation by the magnetic brake. Furthermore, in the present machine, the manual switch for starting the cycle of motions is arranged to not only start the cycle of movements through actuation of the relays controlling movements of the respective slides, after which thesuccessive movements of the cycle are completed automatically, but in addition, certain relays in circuit with o r controlled by the starting switch are arranged to control starting rotation of the spindle; land, indirectly of course, these relays control operation of the magnetic brake to release the spindle, so that its rotation may start.

In the machine of the prior application, the cycle of motions for the carriage and slides includes not only the front carriage and front cross feed slide, but the rear cross slide and there is no arrangement by which it is possible to eliminate from the cycle the movements of any one of the respective slides. In the present improve- Ament, however, the circuits and relays are so drawings, in which Fig. 1 shows a plan view of the automatic lathe, substantially as in the prior application, with features of the present improvement incorporated therein; Fig. la is a detail view of driving connections for thecross slide; and Fig. 2 is a wiring diagram showing the circuits, relays and wiring connections of the present improvement.

Referring to the drawings, it will be seen that the lathe bed is supported on a base frame I and is provided with slide ways 2 and 3, at one end of which the head block 4 is mounted, the head stock being provided with bearings for the spindle 5 for supporting and rotating the work.

The spindle 5 is shown as provided with any suitable face plate 6 and center 'I for supporting and rotating the work; and en'the opposite end of the lathe bed the usual tail stock and center may be mounted, but for clearness the latter are not shown. While centers are shown, a chuck is preferable for most jobs, and the usual chuck may be mounted on the spindle 5 for supporting the work when a chuck is to be used.

The spindle 5, in the present improvement, may be rotated in the usual or any preferred manner, but preferably `a motor 8a or other suitable power may be provided for rotating a clutch magnet Bb freely rotatable on shaft 8f. Bevel gears 8c and 8d respectively on the shaft of motor 8a and on the magnet 8b drivingly connect the motor to the magnet, the clutch disc 8e being slidably splined to shaft 8f. The shaft 8f is arranged to drive through change gears 8g to the-gear 8, secured to the spindle 5, substantially asindicated in Fig. 1. When magnet 8b is energized the clutch disc 8e is drawn into contact with the magnet 8b so that the spindle 5 will be driven by motor 8a through the above described connections. The usual apron carriage or main slide 9 is mounted at the front of the lathe on the slide way 2 for longitudinal movement along the bed parallel to the axis of the spindle. A tool carrying cross slide I0 is mounted on suitable ways on the carriage or main slide 8, for movement transversely thereof toward and from the axis of the work carried by the spindle. One or more tools I2 may be mounted on the cross slide I0 by the usual clamping means I3.

As will be seen, the main slide 9 is held to the bed of the lathe by a suitable'bracket I4 and may be moved longitudinally of the bed by a lead screw I5 engaging a nut I6 carried by the apron Il of the carriage or main slide 9. The cross slide I5' is likewise adapted to be moved transversely of the main slide 9 by a lead screw I8, preferably adapted to be rotated by bevel gears I9 and I9a, gearing it to a vertical shaft 29, supported in the apron Il of the main slide 9. The shaft 26 is provided at its lower end with a bevel gear 2l meshing'with a corresponding gear 22 held for rotation in a xed fork 23 formed as part of the apron Il, or otherwise secured thereto, the bevel gear 22 being splined to and slidable longitudinally of a splined shaft 2li, as the main slide 9 is moved by the screw I5. With this construction, it will be seen that the position of -the cross slide I9 may be adjusted transversely of the main slide 9 in any longitudinal position of the latter by rotating the splined shaft 22.

At the rear of the lathe on the slide way 3, another longitudinally adjustable slide bracket 25 is mounted and held in place by a cleat 26, thislslide preferably being positioned by hand along the bed of the lathe, but obviously, the usual screw feed may be provided if desired.

A rear tool carrying cross slide 2l is mounted on ways 29. on the slide bracket 25 and is movable transversely thereof by a lead screw 29. The cross slidev 2l is provided with tool carrying means and may carry one or more tools 36 secured thereto, in the usual manner by clamp bolts 3l. The rear tools should be inverted so as to properly engage the work.

The lead screw 29 for the rear cross slide 2l is also adapted to be rotated by bevel gears 32 connecting it with a vertical shaft 33 mounted at the rear of the slide bracket 25. The shaft 53 is provided at its lower end with a bevel pinion 36 meshing with a corresponding bevel pinion 35, held for rotation `in fixed relation to the slide 25, by a yoke or bearing 36, but keyed to and slidably mounted on a splined shaft 3l, so that the rear slide lead screw 29 may be rotated when the supporting bracket 25 is in anylongitudinal position of adjustment. As the connection between lead screw 29 and its driving shaft 3l is similar in every way to the connection between screw I5 and shaft 25 previously described further description of this connection is not thought to be necessary.

n the present improvement the movements of the various slides 9, I9 and 2l are arranged as in the previous machine, to be effected by energizing magnetic clutches; and preferably the clutch magnets are rotated continuously while the motor 8a drives the spindle 5 independently. The shaft 62, extending longitudinally of the lathe bed (shown broken away in Fig. l) is arranged to drive the clutch magnets for normal or cutting speed and rapid traverse. The right end of the shaft 52 is supported in a bearing 93 in a bracket I9 mounted on the right end of the lathe bed and adjacent this bearing the end of the shaft 92 carries a bevel gear 65 meshing with two similar diametrically disposed bevel pinions 46 and lill. The bevel pinion 36 is mounted on the rear, end of y a forwardly extending shaft 69 supported in bearings 49 formed as part of the bracket 65, the shaft 68 being provided with two bevel pinions 59 and 5I meshing, as will be seen in Fig.

l, with bevel gears52 and 53, mounted upon clutch magnets 59 and 55. The shaft 48 may be arranged to drive 'all the clutch magnets by connecting it through change gears 69a'with a motor 98h, or the drive for shaft 22 may be by any other well known arrangement.

The clutch magnet 55 (rotated by pinion 50) is rotatably mounted upon the end of an auxiliary shaft 56 extending longitudinally of the lathe at the front thereof and rotatably supported in a bracket 5l at its right end and in a bracket 58 at its left end, as will be seen in Fig. 1. It will be notedthat in order'to have the magnetic clutches 5ft and 55 in the same line soas to operate them from the same shaft 49, the shaft 56' is mounted below the main slide lead screw I5 and the latter is connected to the shaft 56 by means of two spur .gears 59 and 60connected respectively to the shaft 56 and the right end of the screw I5, so that the screw I5 may be rotated by rotating the shaft 56 from either end.

The right end of the,I shaft 56 carries a clutch armature disc 6I for cooperation with the clutch magnet 54, the clutch disc being slidably splined to the shaft 56, so that the latter may be rotated when the clutch magnet is energized. Similarly the right endl of the splined shaft 24, for rotating the cross slide lead screw I8, is provided with a clutch armature disc 62 slidably splined on the end thereof so that by energization of clutch magnet 55, the shaft 25 may be rotated for feed of the front cross slide.

' The other (rear) bevel pinion '41, meshing with the gear 45, is mounted on the end of a shaft 63, extending toward the rear and supported vin bearings 64 and 65. The shaft 63 carries at its rear end a bevel pinion 66, meshing with a bevel gear 6l, secured to a clutch magnet 68 rotatably mounted on the end of the spline shaft 3l, as will be seen in Fig. l. The right end of the shaft 3l is rotatably supported in a bearing bracket 69 (which also supports bearing secured to the rear of lthe lathe bed. Adjacent the bearing in 69, the shaft 3l carries a clutch armature disc 'l0 slidably splined on the shaft for rotating the latter by cooperation with the clutch magnet 68, when the latter is energized. By this means, it will be understood that the rear cross slide 2l may be operated for rotation of the lead screw 29 (this for rapid traverse as explained later).

The left end of the longitudinally extending connecting shaft 92 is'supported in a suitable bearing'bracket 1I and carries adjacent thereto a bevel pinion l2 meshing with oppositely rotated bevel pinions 13 and lll, so that these pinions are rotated from bevel gear by the shaft 138. The front bevel pinion 'I3 is secured to the end of a short shaft 'I5 rotatably mounted in a bearing bracket I6 secured to the left end of the lathe bed, as will be seen in Fig. l, this shaft l5 carries a spur'gear 'VII meshing with a similar gear I8 mounted on a shaft 19 havingv bearing in the bracket 'I6 and extending forward through a bearing in a bracket arm 89, shown as part of the bracket 58, previously referred to as supporting the left ends of the shaft 56 and screw I5. This same bracket also supports the left end ofthe shaft 26.

The shaft 'I9 carries at its front end a change gear or pick-off pinion SI meshing with a change gear 82 mounted on the end of a shaft 83, extending parallel with the shaft 'i9 and rotatably supported in the bracket 89 and a bearing lug 86 formed as part of the bracket 16. It will be understood that with the gears 8I interchangeable\with other gears the relative speeds of rotation of the shafts 'I9 and 85 may be varied.

The shaft 83 has mounted thereon two bevel pinions 85 and 86 meshing respectively' with bevel gears 81 and 88 secured to clutchv magnets 89 and 90, which are accordingly rotated in the opposite direction from the corresponding clutches 58 and 55 on the opposite ends of the respective shafts 56 and 24. The clutch magnet 89 is rotatably mounted on the left end of the shaft 56 in position to cooperate with a clutch armature es slidably spuned on lthe left end of the shaft 5t so that the latter will be rotated to move the carriage or main vslide 9 to the left, that is, for forward movement when the clutch magnet 89 is energized. Similarly the clutch magnet 90 is rotatably mounted upon the left end of the splined shaft 24 for cooperation with a clutch armature 92 slidably splined on the left end of the shaft 24 so that the shaft 24 may be rotated when the clutch magnet 90 is energized for the forward or in movement of rthe front cross slide i0.

The rear bevel gear 14, which as previously described meshes with the driven bevel gear 12 on the left end of the shaft 42, is mounted on a short shaft 93 rotatably mounted in a bearing bracket 915 and carries on its rear end a spur gear 95 meshing with a similar gear 96 mounted on a shaft 91. One end of shaft 91 has a bear- .ing in the bracket 94 and the other end in a curved bracket 98 extending rearwardly from the lathe bed. The rear end of the shaft 91 is connected by change gears 99 and |00 with a parallel shaft i 0| also rotatably mounted in the bracket 98. The shaft |0|- is provided with a bevel pinion |02, meshing with a bevel gear |03, secured to a clutch magnet |04 rotatably mounted on the left end of the rear feed shaft 31, as will be seen in Fig. l. Th clutch magnet |04 is adapted to cooperate with clutch armature |05 slidably splined to the end of the shaft 31, so as to cooperate with the clutch magnet |04 and rotate the shaft 31 when the magnet is energized.

From the described gearing arrangement, it will be seen that the various clutch magnets X89, 90, H06; 50, 55, 68) for the movements o'. the main carriage 9 and slides l0 and 21 are rotated in unison by the power applied to the .shaft 48. By tracing the gearing connections, it will be seen that the main slide or carriage 9 is moved in the forward direction, that is, toward the left, during the cutting operation by the magnetic clutch 89, and for rapid traverse toward the right, forits return movement, by the clutch magnet 54. It will also be seen that the forward orin movement of the front cross slide i0 is effected by magnetic clutch 90' operating the splined shaft Ztl, while the return movement, back to initial position, is effected by the clutch magnet 55, it will be seen is rotating at higher speed. Similarly, the rear shaft 3l is rotated for the forward or in movements of the rear cross slide 21 by the clutch magnet |09, and for its return movement by thehigh speed clutch magnet 68. It will also be understood that by means of the lchange speed gears 8|82 and 99-|00, f'or normal feeds the relative speeds of rotationof the clutch magnets 89, 90 and .|04 for the forward and in movements maybe varied according to requirements.

For energizing the respective clutch magnets, various circuits are provided as more particularly shown in Fig. 2, and through suitable re- `lays and auxiliary circuits, automatic control of the succession of movements of the various slides is predetermined by switches operated by the respective slides shown in Fig. 1.

Preferably two types of switches are used; one type being referred to as limit switches |01, |08 and |09, which comprise spring contact ter- `minals normally arranged with suflicient resiliency to close the circuit, but provided with outwardly flaring ends H0, so that the circuit may be broken by the entrance between the spring members of a bar or operating member of insulating material, projecting from a bracket ||2 carried by the respective slides 9, |0 and 21. In Fig. 1, the contact terminals of the limit switch |01 are shown in closed position (insulating bar being withdrawn) and those of |08 closed and |09 open.

The limit switches just described (|01, |08, |09) determine the initial positions of the respective slides and therefore, by opening the circuits of the rapid traverse clutch magnets limit their return movements of the respective slides. The clutch magnets are preferably operated on volt current and since the limit switches are arranged directly in the circuits of the respective clutch magnets for rapid traverse return movements opening the switches when the slides return to their starting or initial positions immediately deenergizes the clutches and stops the movements.

Obviously, it may be desirable at times to vary the initial or starting or out limit positions of the respective slides and accordingly, the positions of each of the limit switches are adjustable, the limit switch |01 being mounted on a slotted bracket ||2a sc) that by means of a suitable clamping screw ||3, its position longitudinally of the lathe bed may be adjusted. Similarly, the limit switch |08 is mounted for adjustment relative to the cross slide I0 by means of a slot ||4 and clamping screw H5, as indicated in Fig. 1. The rear cross slide limit switch |09 is likewise adjustably mounted on a slotted bracket l i6 and may be clamped after adjustment by a suitable screw at |I1, so that the return limit or initial position of the slide 21 may be varied.

For stopping the forward and in.movements and initiating the succession of movements of the cycle, as will be more fully described later, the respective slides operate contact,v lever switches ||8,||9 and |20 for controlling relays,

preferably operating in low potential auxiliarycircuits. The contact switches are mounted to be operated by the respective slides at the ends of their forward movements; for instance, the contact lever switch |8 is mounted on a supporting block |2I, so as to be in position to be operated by a` lug or projection |22 carried by the carriage or main slide 9. The contact lever ||0 is preferably adjustable relative to the carriag'e 9, the block |2| being arranged to slide along a slot in the plate |2|a. However, the contact lever switch l i9 is preferably mounted at |28 to the slide 9, in fixed relation to the cross slide l0. The contact lever switch |20 is likewise mounted at |24 on the bracket 25 in fixed relation to 4the rear cross yslide 21. The contact switch |9is adapted to be opened at the end of the forward movement of the fro/nt cross slide i0, by a finger or lug |25 adapted toV be adjustably clamped by a screw nut |26 on a slotted bracket |21, secured to the slide |0, .as shown in Fig. l. A similar actuating lug |28 'is adapted to open the contact switch |20, the lug |28 being adjustable and clamped by wing nut |28 to a limit slotted bracket |30, secured to the side of the rear cross slide 21. The relative adjustment between the actuating lugs (|25 and |28) and the corresponding contact lever switches (||9 and |20) may be obtained by any other well known means and when desired any well-known micrometer screw adjustments may be employed for close setting.

As with the machine of the prior application the various movements of the slides are arranged to follow a predetermined cycle, the movements being preferably controlled by relays and circuits substantially as shown in the wiring diagram, Fig. 2. As with the prior arrangement, there are six relays, A, B, C, D, E and F, the operation of which for starting 'the cycle is controlled through a starting relay G. The starting relay G, as will be explained later, is in the high potential circuit, but the relays A to F are preferably operated on low voltage current from a motor generator I3|, one side of which is grounded at |32. The circuit |33 from the 10 volt generator passes to a switch arm |34 of the main switch, and when the switch arm is closed to contact shown the current passes to circuit |35 which is connectedto the armature |36 of the starting relay G. This armature |36, when the relay G is not actuated, is resiliently held against a contact to the circuit |31, which by suitable branch lines passes to the respective magnets of the relays A, B, C, D, E and F, the magnet circuits being completed to ground through the respective slide operated lever con-A tacts ||8, ||9 and |20 and another ground asI 'A and C, the circuits |38 vpass to the contact cooperating with lever contact switch 9 and then to ground at |39. The operating circuits of the relays B and D are similarly completed to ground through circuits |40 to the contact cooperating with lever contact switch |8 and then to ground |4I. The ground circuits of the magnets of relays E and F in this improvement diier considerably from those described in the previous application. For instance, the ground circuit |40a lfrom relay magnet E is divided and branch |40b goes to join circuit |40 and then to ground through contact lever ||8 fand. ground The other branch |40c goes to a limit switch |08a, similar to the interrupter |08, and preferably mounted in the same plane therewith for operation by a similar insulator plug |||a (for clearness |08a and |||a are shown at one side of |08 and and this switch (|08a) when `closed completes the circuit to ground |40d. For relay magnet F the circuit to ground is through circuit |42 to the contact of an auxiliary lever contact switch |42a normally held open by spring |42b butadapted to close on contact |42c to complete the circuit |42d to |20 and then to ground at |43.

For closing the ground circuit |42 to |4211 the contact lever |42a may be provided with a roller |42f with which the beveled end |1a of a square rod |1b cooperates. in Fig. 1, is preferably mounted upon the main slide or front/carriage |1, anddnay be adjusted relatively thereto by a thumb screw |1c. it will be seen that the auxiliary contact lever |420, may be actuated to close the ground of the relay F at any point in the forward run of the front carriage 9, and by removing the rod |1b the ground to |43 will not be closed.

The clutch magnets (54, 55, 68, 89, 90, |04) The rod |1b as will be seen Thus are preferably energized by high potential or 110 volt current and the main plus circuit line is indicated at |44, which passes to the arm |45 of the main double arm switch SM and when this switch is thrown to the right, the plus side |44 of the line circuit is completed to circuit |46, which, it will be seen, divides, one part going to the motor |41 of the motor generator and thencev by circuit |48 to the negative side |49 of the main line 110 volt circuit.

Another part of the plus circuit |46 goes to the armature |50, of relay'E which when not energized (armature up as shown in Fig. 2) closes on circuit |5|, which is connected to the switch arm |52 of starting switch SS. The starting switch SS (|52) is normally closed on circuit |53, which, it will be seen, passes through the magnet of the starting relay G. Instead of going immediately to the negative side of the circuit from relay G, the circuit passes by lead |53a to the magnet of a relay H, controlling rotation of the spindle. The circuit |49a from relay H preferably passes through a 1000,0hm resistance |491) and thento the negative side of the main line circuit |49.

Two branch circuits of circuit |5| pass to contacts of a two arm contactor or automatic switch 54 through which they connect with circuits |55 and |56, the circuit |55 passing through the main slide limit switch |01 and then to the main slide return clutch magnet 54 (MS Rgt) and by |51 to the negative side of the main line circuit The circuit |56 passe s to the rear slide limit switch |09 and then to the rear slide return clutch magnet 68 (RS Out) and from there by |58 to the negative side of the main line circuit |49.

. It will be seen that the automatic double contactor |54 is operated by a branch of the positive main line circuit |46, which passes through an operating coil |59 and then to the negative circuit |49.

Going back to relay E, it will be seen that if the armature |50 is drawn down by actuation of the magnet, the positive circuit |46 is carried through to circuit |60, which is connected to the armature |6| of the relay B and from the armature |6|. when in normal up position (that is magnet B not energized), the circuit is closed to circuit |15 directly to limit switch |00 and thence l to the front slide return clutch magnet (FS Out) and then through |16 to the negative side |49.

In the present improvementthe circuit |60 has a branch |62 leading to the armature |63 of the relay F and when relay F is energized, the armatureA |63 closes on circuit |64, which passesto the in-feed rear clutch magnet |04 (RS In) and thence through |65 to the negative side |49 of l |10 of relay C. This armature |10, in normal up position, with the relay magnet deenergized, closes to circuit |1| which goes to armature |12 of relay magnet D and thence, when the relay D is energized to circuit |13; the latter going to the main slide clutch magnet 89 (MS Lft) and from there by |14/ to the negative side |49 of the circuit.

The positive main line circuit |46 in this new machine has a branch |46a leading to the armature H1 of 'the spindle control relay magnet H, the armature when the relay is not energized being held closed on`circuit H2 which is connected with the magnet of a relay K, for controlling the energization of a brake magnet 8h, and then through lead H3 to the spindle clutch 8b and from there through H4 to .negative side |49. The main circuit |46a also has a branch to the armature K1 of the brake control relay K, the circuit passing from the armature K1 by circuit lead K2 to the brake magnet 8h, and then through lead Ks to the negative side |49.

Preferably the brake magnet is a clutch magnet on the same shaft f with the spindle clutch magnet 6b and cooperates with an armature disc 8k integral with the disc 8e, and therefore slidably splined to the drive shaft 8f of the spindle. The brake magnet 8h is held from rotation in any suitable manner as by bracket clip 8m. It will be -seen that the circuits of the relays l-l and K and the respective armatures H1 and K1 are so arranged that when the spindle clutch magnet is energized the brake magnet is deenergized and vice versa. Accordingly, when the spindle is not rotating it will be held against rotation by the brake clutch 8h. Obviously, any suitable magnetic brake scheme may be employed.

If the arm |45 of the main line switch SM is thrown to the left, the positive main line circuit lllll is connected to circuit |11, which by suitable branches is connected with three switches S|, S2 and S3 normally open as indicated in Fig. 2. When the Si switch arm |18 is closed the circuit |11 is connected to circuit |19 which joins with circuit |55 going through the limit switch |01 to clutch magnet 54 and then through |51 to the negative side of the circuit |49.

When the contact lever |00 of switch S2 is closed, the circuit |11 is completed to circuit |8|, which, as will be seen, is connected to circuit |56 going through limit switch |09 to the rear return clutch magnet 68 and then tothe negative side |49.

When the contact arm |82 of switch S3 is closed, the positive circuit |11 closes to circuit |83 which joins circuit |15, the latter passing through limit switch |08 and then to the front slide return clutch magnet 55 and from there through.|16 to the negative side |49 of the line circuit.

The operation may be described as follows in connection with Fig. 2,` assuming that the motors 8a and 48D are running at substantially constant speeds, the Various elements being there shown substantially in normal idle positions. The rst step is to close the main switch SM (arm |45 to right) so that the L plus 110- volt circuit |44 is completed to circuit 46 and the volt circuit |33 from the generator |3| by arm |34 is closed on circuit |35. The circuit |46 to the motor |41, starts the latter, the circuit being completed directly to the minus side |40 of the 110 volt circuit through |48.

Another branch of the plus circuit |46 by passing through the coil |59 closes the double contact switch |54, this branch of the circuit |46 being connected directly to the minus side |49.

acento@ The main division of the plus circuit |46, however, goes through armature |50 of relay E and then back through circuit |5| and through starting switch arm |52, which, as previously indicated, is closed, and then by circuit |53, through the coil oi relay G, through line |53a to the coil of relay H then through |4911, and resistance |491) and to the negative side of the mainline circuit |49. Accordingly the starting relay G is energized and draws down the armature |36 to break the circuit so that the low potential current starting in circuit |35 cannot pass to circuit |31 to energize or operate any of the relays A to F inclusive. Likewise, the energizing of relay H draws'down the armature H1 and breaks the circuit from |46 and |4611, to Hz so that the brake clutch 6h remains en ergized. f

At this time it will be understood that all the slides are in their initial positions, that is, the main slide 9 is at its starting position at the right; the front cross slide |0 is in its initial or full out position; and the rear slide 21 is in its out position, thus all of the limit switches |01, |08, |08a and |09 are held open. With the slides all back, it will be understood that all of the lever contact switches B0, 9 and |20 are closed, so as to ground and complete the control relay circuits when the cycle is started, but contact lever |42a in the rear slide ground circuit |42 is open so that this ground cannot be completed until the contact lever is operated by the bar |1b. l'

`The momentary starting switch lever |52 of the starting switch SS is now depressed, thus breaking the circuit |5||53, |53a through the coils of relays G and H, thereby permitting the respective armatures |36 and H1 of the relays to rise to close circuit |35 on circuit |31 so as to energize or place in condition to be energized when the grounds are completed the series of relays A, B, C, D, E and F; and to close circuit |46a on circuit Hz-Ha so as to energize spindle clutch magnet 8b and start rotation of the spindle 5, the circuit being ,completed through H4 to minus side |49.

It will be noted that the circuit Hz-Hs energizes the magnet of relay K and draws down armature K1 to break the circuit |46a-K2--K3 to deenergize the brake magnet 8h and release the spindle for rotation. The circuits |31 of the several relays are completed through circuits |38 and ground |39 for relays A and C; circuit |40 and |40b and ground |4| for relays B, D and E, with the additional ground circuit |40c through limit switch 08a to ground 40d for relay E; circuit |42, v'auxiliary lever contact |42a,-|42c, circuit |42d and ground |43. The relay armatures are thereby all drawn down except armature |63 of relay F, and the circuit |46 through the armature |50 (relay E) to circuit |5| is broken so that the starting key SS maybe released without energizing relays G and H, and current in circuit 46 through armature |50 is carried to circuit |60, which *oing through armature |6| (relay B energized) to the lower circuit |66 will carry the plus current to armature |61 of relay A and through circuit |68 to clutch magnet 90, marked FS In, the latter being the clutch magnet for in feed of the front cross slide, the circuit being complet d by line |69 to the negative main line circuit |49.

The in movement of the front cross slide |0 thus started will continue until the lever contact |9 is broken by the tappet lug |25, whereby the ground circuit |38, |39 will then be broken, following which the armatures of relays A and C will be released and restored to normal up positions. The circuit |69 to the clutch magnet being thus broken and thein movement of the slide |9 will be stopped with the tool in position for making the cut on the work W, which will be effected by forward movement, that is, movement to the left, by the main slide 9. Now tracing the plus current through circuit '|50 and through armaturev 6| which is down, to circuit |59, it will -be seen that the latter is connected with armature |10 of relay C, the magnet of which has been deenergized by the breaking of the ground circuit |38|39, so that the relay armature |10, being up, closes on circuit |l| vcarrying the positive current to armature |112, which is down (D being energized) and by circuit |73 the current is carried to theclutch magnet 09, markedMS Lft, and thence by lead |l| to the negative side |49 of the main line circuit. Left feed movement of the main carriage or main slide 9 is, therefore, started and the tool |2 is moved to the left for the cutting operation on the work W.

As distinguished from the arrangement in the previous applicatiomit will be seen that armature |63 of relay F is up at the start of the left or forward movement of the carriage or main slide 9, because the contacts |42a at |42c of the' ground |42|43 are open. When, however, the beveled end |'la of the bar Hb, which has previously been adjusted to start the rear slide at the preselected point in the movement of the.

carriage, engages the roller |42f on the contact lever |4211. then the ground circuit M12-|43 is completed. The relay F is then energized from circuit |3l and the armature |63 is drawn down to close branch circuit |62 (from |60) to circuit |50 and the clutch magnet |09, RS In, is energized to start forward or in movement of the rear cross slide 2l. In this way the in movement of the rear slide may be started vat any time before the end of the run of carriage 9. Incidentally, it will be seen that by removing the bar |'lb from the carriage 9, the contact lever Mila will not be actuated and the rear cross slide is eliminated from the cycle.

The left or forward movement of the main slide 9 after being started, as above indicated, will continue until the stud |22 thereon engages the contact lever ||9 and breaks the ground circuit |00 and thus deenergizing the magnets of relays B and D and breaking the ground circuit |00!) of relay E, but since the cross slide |0 is all the way in the limit switch |00a is closed and the armature |50 of relay E is held down by ground Md. Deenergizing relays B and D, however, allows the armatures |6| and |12 to return to normal up positions and the circuit H3 to clutch 89 will be broken so that left movement of the main slide 9 is stopped. At the same time the armature |6| of relay B, by being drawn up, closes the circuit |60 to circuit |`|5 and through limit switch |09, which is closed because the front cross slide l0 is in` its forward or. in position, and since circuit |15 passes to the FS Out clutch magnet 55, the latter will be energized, to bring into action the rapid traverse for return of the front slide |0 to initial out position at high speed, the circuit |ll5 being completed through |16 to the negative side ||9 as previously indicated.

-As soon as the` front slide H0 reaches initial position, two things now happen, the limit switch |08 will be opened by the bar to stop the return movement of the cross slide I0, and the auxiliary bar |||a, will open limit switch |00a and break the iinal ground circuit |40c|40d of relay E and allow armature |50 to rise.

At this point, it should be note-.i r "hen the front slide I0 starts on its return to initial position, the lever contact switch ||9 is again closed, but owing to the fact that the volt circuit is broken at other points (relay B deenergized) the main line circuit of the slide for in movement will not be again closed until the cycle is repeated.

The rear slide 21, the in movement of which is started bythe bar Ila-Hb, will continue its in movement by energization of clutch magnet |05 RS In until the trip arm V|29 engages the contact lever |20 and breaks the ground circuit |62, |43, thus deenergizing the magnet of relay F, so that the armature |63 thereof will return to normal up position and the circuit |65 to the RS In clutch magnet |04 will be broken, thus stopping the in movement of the rear slide.

When the armature |50 of relay E is lifted,

upon deenergization of relay E by breaking the ground |40d, the ground of contact lever ||9 being also broken, the plus circuit is again closed to circuit |5| and through the double contactor |59 to circuits |55 and |56. Tracing circuit |55, it will be seen that 1the current passes through the limit switch |07, which is closed because the main slide 9 is at the extreme left, and energizes the rapid traverse clutch magnet 56, marked MS Rgt, for high speed return movement of the main carriage or slide 9. When the main slide 9 reaches its initial or starting. position, the switch bar by entering the limit switch |01, will break the'circuit |55 and stop the return movement of the main slide.

The current in circuit |56 (from double contractor |5), passing through limit switch |09, the latter being closed, since the rear cross slide 21 is still in its forward position, will energize clutch magnet 68. marked RS Out, and thus return the slide 2l to its initiale position at relatively high speed or by rapid traverse. Upon the rear slide 2l reaching its initial position, the switch bar thereon will open the limit switch |09 and deenergize clutch magnet |58 to stop the return movement.

It will be seen that, in the present arrangement, the carriage or main slide 9 cannot return to the right, even though theground Contact HB is opened by engagement of |22 therewith, until front cross slide |0 returns to initial position and opens limit switch |09a and breaks the auxiliary ground Mild.

Furthermore, it will be noted that upon the start of the return movements of the main slide 9 and the rear slide 2l by the closing of armature |50 on circuit |5|, this circuit also carries the current through starting switch SS|52, circuit |53, relay G and relay I-I, thus breaking low potential circuit |35|3`l and breaking the high potential circuit |46a-H2, through relay K, circuit H3 and clutch magnet 8a, to deenergize the latter and stop rotation of the spindle 5. This deenergizes the relay K andpermits armature K1 to rise so that current from circuit Ma passes to circuit K2 and the brake magnet 9h is energized, and substantially instantly stops rotation of the spindle. The brake magnet will then xedly hold the spindle so that the finished piece may be removed and a new piece inserted.

The cycle of movements having been completed and the slides 9, I0 and 21 are all back at theirv initial or starting positions ready for another cycle and as just stated rotation of the spindle is stopped and the spindle is held by the brake clutch. After inserting the Work piece and again depressing the starting switch SS, the cycle is repeated automatically, and .may be continuously repeated without further attention from the operator, except to remove the finished pieces and insert new pieces.

If at any time it becomes necessary to return the slides to their initial positions before the completion of a cycle of movements, the main switch SM is thrown to the left, thus cutting out the low potential circuit i35 and carrying the current in the L plus circuit idd to circuit lll and the manual switches Sl, S2 and S3. Cutting out circuit M6 stops the motor generator and releases the contactor switch l54 and deenergizes the magnet of starting relay G, but

there is no low potential current so the relays A, B, C, D, E and F are idle; and relay H is deenergized, but the current through iiB-illa is stopped so that the spindle clutch 8b will not be energized for rotation of the spindle even though the brake clutch is deenergized.

Now if it is desired to return the main slide 9 to its initial position, the key bar H8 of switch Si is depressed, closing circuit ill to lig-|55 and the current passing through circuit i55 (limit switchil closed) will energize the rapid traverse return magnet 5 1?, and thus bring the carriage or main slide 9 back to its initial position, at which time the switch bar i l l will again open the limit switch il, and stop the movement.

Similarly the rear cross slide 2l, if and when it is operated, may be returned to its initial position by depression of the key bar 80 of switch S2, thereby closing circuit H11 on lBl--l 56 and thus directing the current by circuit 56 (limit switch H09 closed) to the rapid traverse return clutch magnet 68, RS. Out and return movement of the slide 2l will continue until the .circuit is broken by the bar lil of slide 2l opening the limit switch H09.

Likewise by depressing the key l82 of` switch S3, the circuit lll is closed on HB3-H5 which directs the current through circuit H5 (limit switch m8 closed) to energize the rapid traverse return clutch magnet 55 (FS Out) and return the front slide l0 to its starting position. When the front slide Il) reaches its initial position, the switch bar llfl opens the limit switch E08 and by breaking the circuit H5, stops the return movement.

The present improvement differs from the automatic lathe of the previous application in that means is provided for completely eliminating the rear cross slide from 'the cycle Without disturbing the rest of the cycle of movements` This, as previously pointed out, is effected by kkeeping the relay F from becoming energized,

and this may be done by keeping the ground MS2-i133 open in any suitable manner. In the present --insta'nce it is only necessary to remove the bar ilb, and thereby prevent the operation of contact lever lll2a, to prevent the operation of the rear slide 2l in the cycle. l

Obviously the rear cross slide may be dispensed with entirely, or it may be mounted upon a longitudinally movable carriage similar to the main slide 9.

While the preferred form of the improvement has been shown and described, it will be understood thatlthe electrical control through prearanged cycles of movements 'for the various 'slides Amay be arranged differently or different varieties of tools may be controlled in substantially the same way without departing from the spirit and scope of the invention.

What I claim is:

1. Anautomatic lathe comprising in combination a rotatable work spindle, a clutch magnet for effecting rotation thereof, a tool supporting carriage, a tool thereon movable longitudinally and transversely relative to the spindle, clutch magnets for eiecting forward and return movements of said carriage,' circuits for energizing the respective clutch magnets, a manually operated switch controlling said energizing circuits for starting rotation of the spindle and movements of the tool, switches in said circuits arranged to be operated by movement of said tool to control the movements of the latter and for deenergizing the spindle clutch magnet and a magnetic brake arranged to be energized to stop rotation of said spindle when said spindle rotating magnet is deenergized.

2. An automatic lathe comprising in combination a rotating work spindle, a clutch magnet for eifecting rotation thereof, a magnetic brake for stopping rotation of said spindle, a tool supporting carriage, a tool thereon, clutch magnets for effecting forward and return movements of said carriage, circuits for energizing the respective magnets, a manually operated starting switch for controlling energization of the respective magnets for starting rotation of the spindle and movements of the tool, and switches in said circuits arranged to be ,operated by the movement of said tool for controlling movements of the latter, one of said latter switches being arranged to stop rotation of said'spindle at the end of the carriage return movement.

3. An automatic lathe comprising in combination a rotatable work spindle, a clutch magnet to effect rotation thereof, a carriage movable longitudinally of said spindle, a tool supporting slide movable. thereon, clutch magnets for eiecting forward and return movements of the carriage and in and out movements of the slide respectively, circuits for energizing the respective clutch magnets, switches in said circuits arranged to be operated by the carriage and slide for controlling energization of the respective clutch magnets to effect movements respectively of the carriage and cross slide, and

-switches operating to energize and deenergize the clutch magnet for rotating the spindle, the operation of said switches being so arranged that rotation of the spindle and the movements of the carriage and slide follow in prearranged sequence.

4. An automatic lathe comprising in combination a rotatable work spindle, a clutch magnet to effect rotation thereof, a carriage movable longitudinally of said spindle, a tool supporting slide movable thereon, clutch magnets for eiecting forward and return movements of the car- .riage and in and out movements of the slide respectively, circuits for energizing the respective clutch magnets, switches in said circuits arranged to be operated by the carriage and 'slide for controlling energization of the respective clutch magnets to effect movements respectively of the carriage and cross slide, switches operating to energize and deenergize the clutch magnet for rotating the spindle, the operation of said switches being so arranged that rotation of the spindle and the movements of the carriage land slide follow in prearranged sequence, and a magnet'arranged to be energized to stop rotation of said spindle when said spindle clutch magnet is deenergized.

5. An automatic lathe comprising in combination a spindle for rotating the work, a. carriage movable longitudinally thereof, a tool carrying slide ovable on said carriage, a tool carrying rear s de, clutch magnets arranged for rotating said, spindle and effecting movements of said carriage and the tool slides, means for energizing and deenergizing said clutch magnets in prearranged succession so that rotation of said spindle and movements of said carriage and slides are effected in predetermined sequence, means arranged to be operated by said carriage to initiate the cycle of movements of said rear slide, said means being adjustable whereby movements of the rear slide may be started at dif-l ferent predetermined positions of the carriage, and independent means for rotating said spindle rotating clutch magnet.

6. An automatic lathe comprising in combination a spindle for rotating thev work, a carriage movable longitudinally thereof, -a tool carrying slide movable on said carriage, a tool carrying rear slide, clutch magnets arranged for rotating said spindle and effecting movements of said carriage and the tool slides, means for energizing and deenergizing said clutch magnets in prearranged succession so that rotation of said spindle and movements of said carriage and slides are effected in predetermined sequence, means arranged' to be operated by said carriage to initiate the cycle of Imovements of said rear slide, said means being adjustable whereby movements of the rear slide may be started at different predetermined positions of the carriage, means for constantly'rotating the clutch magnets for the respective movements of the carriage and slides, and independent means for rotating said spindle rotating clutch magnet. i

v'1. An automatic lathe comprising in combination, a work supporting and rotating spindle,'a carriage movable longitudinallythereof, a tool slide movable on said carriage, a rear tool slide mounted independently of said carriage and movable transversely of the spindle, magnetic clutches for rotating the spindle and eiecting -movements respectively of the carriage and slides, electric circuits for operating the respective magnetic clutches for rotating said spindle and effecting the movements of the carriage and slides, circuit closing contactors operated by and controlling movements respectively of said carriage and the slides for successively effecting said movements in predetermined sequence, and means mounted on said carriage for operating a contactor for-initiating movement'of said rear slide, said means being adjustable so that said movement may be initiated at anypredeter'mined point in the path of movement of the carriage.

8. An automatic lathe comprising a spindle for rotating the vvwork, tool carrying slides having movements relative to the work, a clutch magnet for rotating the spindle, clutch magnets for effecting movements of said slides, operating circuits for relays controlling circuits for energizing said clutch magnets, means operated -by the slides for controlling through said operating circuits the energization of the respective clutch magnets so that movements of the slides follow a prearranged cycle, a starting switch for starting the cycle of movements of the slides and controlling energization f the clutch magnet for rotating the spindle and means brought into action by one of the slides at a predetermined point in the cycle for deenergizing said spindle clutch magnet to stop rotation of the spindle.

9. Anautomatic lathe comprising a spindle for rotating the work, tool carrying slides having movements relative to the work, a clutch magnet for rotating the spindle, clutch magnets for effecting movements of said slides, a relay and operating circuits controlling energization of said spindle clutch, relays and operating circuits ccntrolling energization of the respective magnets for eiecting movements of the slides, means operated by the respective slides in their movements for operating said relays and controlling energization of the clutch magnets so that movements of the slides follow a prearranged'cycle, a starting switch controlling operation of certain of said relays for starting rotation of said spindle and controlling'the cycle of movements of the slides, and means operated by one of the slides at the end of its movement for deenergizing said spindle clutch magnet to stop rotation of the spindle.

10. An automatic lathe comprising a spindle for rotating the work, tool carrying slides having longitudinal and cross-feed movements relative tothe work, a clutch magnet for rotating the spindle, a brake magnet for stopping rotation of the spindle, clutch magnets for effecting movements of the respective slides, circuits and relays controlling energization of the spindle rotating clutch and brake magnets, circuits controlling relays operated by the slides for controlling energization of the respective slide clutch magnets to eiect movements of the slides in a prearranged cycle, a starting switch in the circuit of the spindle clutch relay, a relay in said starting switch circuit for starting the cycle of of movements of said slides and the rotation of the spindle, and means controlled by the slides and operated at a prearranged point in said cycle for deenergizing said spindle clutch magnet and energizing said brake magnet to stop rotation of the spindle.

11. An automatic lathe comprising a spindle for rotating the work, tool carrying slides having longitudinal and cross feed movements relative to the work, clutch magnets for eiecting movement of said slides, circuits and relays operated by the slides for controlling energization of the 'respective slide clutch magnets to effect movements of the slides in a prearranged cycle, a clutch magnet for rotating the spindle, circuits and a relay controlling energization and deenergization of said spindle rotating clutch magnet, a starting switch in the circuit operating said spindle relay, a second relay inthe starting switch circuit for starting movements of the slides in the prearranged cycle and for energizing the clutch magnet for starting rotation of, the spindle, means operated by said slides for causing deenergizaton' of said spindle clutch megnet, and means controlled by said spindle relay for stopping rotation of the spindle when said spindle clutch magnet is deenergized and for holding said spindle against rotation when the 'cycle of movements of the slides is completed.

12. An automatic lathe comprising a spindle for the-work, tool carrying slides movable relative to the work including a carriage having movement parallel with the spindle, a cross slide on the carriage having in and out movements, a

controlled by said carriage for starting the in movement of the rear cross slide at any predetermined point during the forward movement of said carriage, and means to complete the cycle of operation of said carriage and its cross slidel without movement of said rear slide.

ROBERT D. SHAW. 

